Technical Field
This application relates to an aspiration pump and more particularly to an aspiration pump for use in thrombectomy or other vascular procedures.
Background of Related Art
There have been various attempts to break up clots and other obstructing material in grafts or native vessels. One approach is through injection of thrombolytic agents such as urokinase or streptokinase. These agents, however, are expensive, require lengthy hospital procedures and create risks of drug toxicity and bleeding complications as the clots are broken.
Other approaches to breaking up clots involve mechanical thrombectomy devices. For example, U.S. Pat. No. 5,766,191 discloses a cage or basket composed of six memory wires that expand to press against the inner lumen to conform to the size and shape of the lumen.
U.S. Pat. No. 6,090,118, incorporated herein by reference in its entirety, discloses a wire rotated to create a standing wave to break-up or macerate thrombus. The single wire is less traumatic than the aforedescribed basket device since it minimizes contact with the graft wall while still effectively mechanically removing thrombotic material.
U.S. Pat. Nos. 7,037,316 and 7,819,887, both incorporated herein by reference in their entirety, disclose another example of rotational thrombectomy wires for breaking up clots in grafts. The thrombectomy wire has a sinuous shape at its distal end and is contained within a sheath in a substantially straight non-deployed position. When the sheath is retracted, the distal portion of the wire is exposed to enable the wire to return to its non-linear sinuous configuration. Actuation of the motor causes rotational movement of the wire, creating a wave pattern, to macerate thrombus.
In neurovascular thrombectomy procedures, the thrombectomy wire needs to navigate tortuous vessels. That is, the wire is inserted through femoral artery and then must navigate small and tortuous vessels as it is advanced to the smaller cerebral arteries of the brain. Within the brain, the carotid and vertebrobasilar arteries meet to form the circle of Willis. From this circle, other arteries, e.g., the anterior cerebral artery, the middle cerebral artery and the posterior cerebral artery, arise and travel to various parts of the brain. Clots formed in these cerebral arteries can cause stroke and in certain instances death of the patient.
Due to the size and curves of the vessels en route to the cerebral arteries from the femoral artery, as well as the size and structure of cerebral arteries themselves, access is difficult. If the thrombectomy device is too large then navigation through the small vessels, which can be as small as 1 mm, would be difficult. Also, if the device is too stiff, then it can damage the vessel walls during insertion. On the other hand, if the device is too flexible, it will lack sufficient rigidity to be advanced around the vessel curves and can be caught in the vessel. The devices disclosed in U.S. Pat. Nos. 8,764,779 and 8,663,259, the entire contents of which are incorporated herein by reference, provide a thrombectomy device for breaking cerebral clots that strikes the optimal balance of flexibility and stiffness, thus effectively having the insertability of a tracking guidewire while enabling high speed rotation to effectively macerate clots without damaging vessels.
After particles have been macerated, especially in neurovascular thrombectomy procedures, it would be advantageous to aspirate the macerated particles to ensure the particles do not travel downstream, which if sufficiently large could result in stroke or even death.